What does methylation of DNA generally result in?

Methylation of DNA generally results in the inhibition of gene transcription. This biochemical process involves the addition of a methyl group to the cytosine bases of DNA, specifically at cytosine-guanine (CpG) dinucleotides. When these methyl groups are added, they can physically block the binding of transcription factors that are necessary for the initiation of gene transcription, leading to a repression of gene expression.

Additionally, methylation can attract proteins that are involved in the formation of repressive chromatin structures. These chromatin modifications can further prevent the transcription machinery from accessing the DNA, resulting in reduced gene expression.

This phenomenon plays a crucial role in various biological processes, including development, maintenance of cellular identity, and the silencing of transposable elements. The reversible nature of DNA methylation also indicates its importance in gene regulation, as it allows cells to respond to internal and external signals by turning genes on or off as needed.